Relay control means and starting means for gaseous lighting devices



July 19, 1949. slTzER 2,476,330

P. RELAY CONTROL MEANS AND STARTING MEANS FOR GASEOUS LIGHTING DEVICESFiled March 22, 1944 fied f ER INVENTOR ATTORNEY 5 Patented July 19,1949 RELAY CONTROL MEANS AND STARTING MEANS FOR GASEOUS LIGHTING DE-VICES Philip Sitzer, Irvington, Sol Lamp Works, Inc.,

tion of Delaware N. J., assignor to Tung- Newark, N. J., a corpora-Application March 22, 1944, Serial No. 527,654

11 Claims.

This invention relates to relays and relay circuits and control systemsincluding the same.

One object of the invention is a novel and improved relay and relaycontrol for starting a gaseous discharge device.

More particularly the invention is particularly applicable to thestarting of conventional fluorescent lamps wherein at starting arelatively large value of current flows and it is required that thecontrol be adjusted to delay its action for approximately one second orlonger and, on the other hand, the contacts be held open during normaloperation of the lamp notwithstanding the reduction in current flowingduring normal operation of the lamp.

An object of the invention is a simple and inexpensive starting controlfor lamp-s of this character which is characterized by operativefunctioning to accord exactly with the demands of a starter of thischaracter.

A further object of the invention is a novel and improved thermalstarting control of the above indicated character.

A further object of the invention is a novel and improved magneticcontrol of the above indicated character.

A further object of the invention is a novel land improved startingcontrol of the above indicated character for a normally closed startingcircuit.

A further object of the invention is a starting control of the aboveindicated character for a Vnormally open starting circuit.

A further object of the invention is a novel and improved relay andrelay control.

Further objects of the invention will hereinafter appear.

For a better understanding of the invention reference may be had to theaccompanying drawings wherein Fig, 1 is a diagram of a relay circuitillustrating the principle of the invention;

Fig. 1A is a circuit diagram of a control system embodying themodification of Fig. l;

Fig. 2 is a diagram illustrating the modified relay embodying theprinciple of the invention;

Fig. 2A is a circuit diagram of a control system embodying themodification of Fig. 2;

Fig. 2B is a graph illustrating the functioning of a relay embodying theinvention of Figs, 2

and 2A;

Fig. 3 is a circuit diagram of la modified starting means for gaseousdischarge lamps.

Referring to Fig. 1 of the drawings, I have illustrated one embodiment`of my improved relay comprising switch control contacts I0 which arethermally controlled, the details of the thermal mechanism being omittedfor convenience in illustration. The thermal mechanism is controlled bya heater element Il which is energized by the current flowing in thecircuit I4, I5. A resistance element 20 is connected in parallel withthe heater element II. The heater element II of the thermal relay ismade of a material or metal with a high positive temperatureco-efiicient of resistance, as for example of a wire of tungsten, iron,nickel, etc. which have positive temperature coefficients of resistance.The resistance element {it}` has very little or no positive temperaturecoefficient, as for example, being made of a wire of a metal such asNichrome which has little or no resistance change with changes intemperature or changes in volume of current ilowing. The action is suchthat there will be less percentage change of current through the heaterelement II for any change of current flowing in the circuit I4, I5 thanthere would be without this particular arrangement. This voccurs becauseof the large change in resistance in the heater element I I with changesin current due to its positive temperature coefiicient of resistance,that is with increase in current there is an increase in temperaturewhich causes the resistance of the heater element II to become greater,thereby causing a greater percentage or proportion of the total currentowing in the circuit I4, I5 to flow through the shunt resistor 20 andvice versa. By making the shunt resistor element 2U of some material,alloy or metal which has a negative temperature coefficient ofresistance, such as carbon, or which has negative resistancecharacteristics such as certain of the silicon carbide compounds, namelyby having the resistance of the shunt element 20 vary inversely withrespect to the resistance of the heater element I I a still greaterdifferential in the current flowing in the two elements is obtained withchanges in the total current flowing. With this arrangement changes inthe total current flowing in the circuit I4, I5 are reflected to asubstantially lesser extent in the element II, that is the percentagechange in the current flowing in the element Il is substantially lessthan the percentage change in the total current flowing.

The invention is particularly applicable to the starting of gaseousdischarge devices, such for example, as the fluorescent lamp Aillustrated in Fig. 1A.

The fluorescent lamp A is provided with the conventional heatingelements I2 at each end of the tube and in the conventional manner theheaters I2 of the lamp are connected in series with a conventionaltransformer choke I3. The heater element II of the thermal relay isconnected in series with the line I4 from one side of the circuit, theline I5, the two heating eleinents I2 and the line I6 leading to theother end of the choke coil I3. The heaters l2 are connected on one sideby the wires Il to the switch contacts I of the thermal relay and aconventional condenser I8 is shown connected across the switch contactsI0. The switch contacts Ill are normally closed, that is closed when theline switch I9 is open or the lamp A is not operating. When the lineswitch I9 is closed starting current flows through the circuit, heatingthe filaments I2 at each end of the lamp and also the heater element IIof the thermal relay. After a suitable time delay the contacts I0 of,the relay snap open and if the lamp lights by discharge between theelements I2 these switch contacts I0 are retained open due to therunning current of the lamp which flows through the heater element I Iof the relay.

This control is effected notwithstanding the large change in the volumeof current ilowing in going from starting condition to the runningcondition, for example with .8 of an ampere owing at the initialstarting the time delay of say, one second, for heating the heaters I2may be ob- Itained before the switch contacts IU are opened `and eventhough the current iowing in the circuit during the normal operation ofthe lamp should drop to half or below, say to .25 ampere for normalrunning, the heater element is sup- ',plied with a suillcent current tohold the contacts IIJ open against the bias tending to close them.

Any suitable type of thermal switch may be employed as for example thebimetallic type or .the vane type. In either case the heating element IIis preferably enclosed in an evacuated envelope II so as to preventoxidation of the element at high temperatures at which the elementshould be run for best results. An example of the vane type of switchwhich may be used is illustrated in Fig. 8 of Schmidinger Patent2,133,309 wherein the switch contacts 39 and 44 are the contacts I0 ofthis application and the heater element 43 is the heating element I I ofthe application.

A modified relay and circuit control is illus- 'trated in Fig. 2. Thecircuit is indicated at I4, i5, the thermal relay contacts are indicatedat I0 and the heating element for the thermal switch device is indicatedat 2|. The heater ZI has connected in series with it a resistanceelement 25 having a positive temperature coeiiicient such for -exampleas of tungsten, nickel or iron and a resistance element is connected inshunt of the character described above with respect to Fig. 1 land Fig.1A. For example, the resistance element 20 may be of Nichi-.ome or otherresistor element with a fairly constant resistance with temperaturechanges, or it may have a negative coefcient, and as indicated, theseries combination consisting of the resistor element and the Iheaterelement 2I of the thermal relay is connected in parallel with theelement 20. The element 25 is placed .in an evacuated envelope such asthe envelope II' of Fig. 1A so that it is not oxidized or harmfullyaffected in any manner when heated to a red or white heat. The action ofthis control is to allow a greater percentage of -the total currentflowing to pass through the heater element of the thermal relay, whenthe total current is low in value than at higher valuesof total current,namely at low values of current the element 25, such for example as oftungsten. wire, has a proportionately low value of electricalresistance. At higher values of current the resistance of the tungstenelement increases at a much greater proportionate rate than theresistance of the other elements of the circuit which decreases theproportional amount of the total current that ilows in the path composedof the tungsten heater element 25 and the heater element 2 I. The heaterelement 2| is of course oi a character so as not. to oppose thecontrolling function of the element 25, namely the element 2I must nothave an appreciable negative coeicient at least in sulcient amounttaking into consideration the proportions of the resistance elements 2Iand 25 to offset the stabilizing effect of the element 25 with changesin total current flowing. The element 20 is a resistance either havingno appreciable positive temperature coefiicient or one having a negativecoefficient. In the circuit of Fig. 2 and Fig. 2A, the temperaturecoefficient of the heater 2l as indicated need not be a high temperaturecoeiiicient since the element 25 imparts the desired high temperaturecoeiilcient characteristic to the circuit including the heater 2 I Fig.2B illustrates graphs of the currents ilowing in the heater branch ofthe parallel circuit and in the shunt or ballast branch containing theelement 20. The abscis'sas represent total currents and the ordinatesrepresent the current owing in each of these branches. The lower curverepresents the current flowing through the heater 2I and the tungstenresistor element 25 and the upper curve represents the current owing inthe ballast or shunt circuit containing the resistor element 20. Thisshows that with changes in total current flowing the percentage changein the heater branch of the circuit is much smaller than the changes inthe total current flowing, thereby rendering the thermal switchmechanism much less sensitive to changes in current flow. For example,for values of total current above 0.25 ampere with the particularcombination of resistances upon which the graphs are based the currentin the heater element branch changes only a slight amount for muchlarger variations in the total current ilowing. These graphs are basedupon the test results of a circuit in which the element 2| was a pullwire in a vane type thermostatic switch made of 0.0065 Ohmax, theelement 25 was a standard T67 lamp and the element 20 was of 17.82 .010Nichrome wire. The graphs indicate that the operational range of such acontrol unit can be increased greatly without substantially affectingits operation. For example, it can be effectively used to control anyfluorescent lamp within a wide range of capacities, as for example,fluorescent lamps of -capacitiesfrom 15 watts to 40 watts sizes. Forexample, it is found by actual test that the operating time for thethermal switch was 0.82 second at 0.87 ampere total current and 3.07seconds at 0.488 ampere total circuit current.

In Fig. 2A I have illustrated the embodiment of the invention of Fig.v 2as used in the starting of a fluorescent lamp similar to thatillustrated in Fig. 1. In thisl embodiment the operating or heaterelement 2| for the relay contacts I0 has connected in series with it avresistance element 25 having a positive temperature resistance co- Awhenheated to red or white heat.

eiiicient such as that of tungsten, iron, nickel or other materialhaving such a characteristic. A

Nichrome or other resistor element 20 having a the heater element 2| ofthe thermal relay. The

element 25 is preferably placed in an evacuated or gas-filled containersuch as the container II described above in Fig. 1A or else is otherwiseprotected in any suitable manner so as not to be oxidized or harmfullyaffected in any manner The action of this arrangement is to allow agreater percentage of the total current flowing to pass through theelement 2| of the relay when the total curvrent is low in value than athigher values of current.

At low values of current the element 25 has a proportionately low valueof electrical resistance, whereas at higher values of current the fresistance of the element 25 increases at a much vgreater proportionalrate than the resistances of the other elements of the circuit. Thisdecreases the proportional amount of total current that lflows in thepath composed of the tungsten resistance 25 in series with the relayheater filament.

The operation generally of the control of Fig. 2A is similar to thatdescribed above with respect to Fig. lA, namely after the starting ofthe iluorescent lamp A the heating element 2| has suflilcient power tohold the contacts I open notwithstanding the reduced flow of currentthrough Vthe circuit I4 and I5 when the lamp is operating.

The heater element 2| may be a pull Wire or the -ous discharge device isillustrated as of the conventional fluorescent lamp type having a heaterelectrode I2 at either end thereof. The supply lline is indicated ashaving a chokecoil I3 connected in one side thereof and the line asconnected with one end of the heater electrodes I2.'

The other ends of the heaters I2 are connected through the lines 30 and3| with the contacts 3 of the thermostatic switch. The contacts 3 arefnormally open, biased to open position, namely open when the switch I9in the supply line is open `and also open durin-g the normal operationof 'the fluorescent lamp A. These contacts 3 however are closedymomentarily at starting by the heat delivered by the element 4. Theelement 4 is a heater of a metal having a high positive 'temperaturecoefficient, such as tungsten, iron or nickel, etc. and the element 5 isa resistance either having no appreciable positive temperalturecoeflicient, such as of Nichrome or having Va negative temperaturecoeflicient, such as carbon or the silicon carbide compounds. Theresistance of element 5 is much larger than that of resistance 4 so asto predominate thereover, as :for example being 75% to 90% of the sum ofthe itwo. During the normal operation of the lamp the elements 4 and 5are connected across the electrode heaters I2 and accordingly thevoltage drop across the lamp A is supplied to these two elements inseries. The 12R. power of the element 4 is insuiiicient to close thecontacts 3' with only the voltage vdrop of the lamp A applied to theelements 4 and 5. 4At starting, however, namely when the switch I9 isfirst closed substantially the full line voltage v.) is supplied to theresistances I2 and the elements 4 and 5 and the heating power of theelement 4 is then very substantially increased by reason of the relativeproportioning and character of the two elements 4 and 5 as describedabove. This increased power results in the closing of the contacts 3 andthe short-circuiting of the elements 4 and 5 and the consequentreopening of the contacts 3 which are biased to the open positionagainst the heating effect of the element 4. The short-circuiting of theelements 4 and 5 puts the heaters I2 directly across the line with theresultant increased heating of these electrodes so that when thecontacts 3 are opened after the momentary closure thereof the desiredstarting kick is delivered to the lamp A. The voltage drop, asindicated, in the lamp A is then insuiiicient to close the contacts 3against the bias. Thus by rendering the thermal switch sensitive to thefull line voltage but not sensitive to the voltage drop across the lampA to close the contacts 3' a very simple and inexpensive startingmechanism is provided for the lamp. A conventional condenser IB isconnected across the contacts 3'.

I claim:

l. In a control means for a gaseous discharge device having heatingelements therein, a circuit connecting said heaters in series across asupply line, a switch in said circuit which is thermally controlled, acontrolling element for said switch which is energized by the currentflowing through said circuit and through the gaseous device, a resistorelement in parallel with said controlling element, the coeii'cients ofsaid elements being related to each other in a manner to differentiallyproportion variations in the current flowing in the circuit to shiftgreater changes in current flow to the resistor element.

2. In a control means for a gaseous discharge device having heatingelements therein, a circuit connecting said heaters in series across asupply line, a switch in said circuit which is thermally controlled, acontrolling element for said switch which is energized by currentflowing through said circuit and through the gaseous device, a resistorelement in parallel with said controlling element, the coeiicients ofsaid elements being related to each other in a manner to differentiallyproportion variations in the current flowing in the circuit 'to shiftgreater changes in current ow to the resistor element, said switch beingopened by the current flowing through the operating element.

3. In a control means for a gaseous discharge device having heatingelements therein a circuitconnecting said heaters in series across asupply line, a switch in said circuit which is thermally controlled, athermal element for controlling said switch which is energized by partof the current fiowing through said circuit and through the gaseousdevice, yand a resistor element connected in multiple with a circuitincluding said thermal element so as to be energized by a part of thecurrent flowing in said rst-named circuit with the resistances of themultiple paths of the currents through the two elements varyingdifferentially with respect to each other upon variations of currentflow to shift greater changes in current flow to the resistor element.

4. In a control means for a gaseous discharge dev-ice having heatingelements therein a circuit connecting said heaters in series acrossasupply line, a switch in said circuit which is thermally controlled, athermal element for ycontrolling said switch which is energized by partof the current -iiowing through said circuit and through the gaseousdevice, and a resistor element connected -in multiple with a circuitincluding said thermal element so as to be energized by a part of thevcurrent flowing in said-first named circuit with ythe resistances ofthe multiple paths of the currents through the two elements varyingdifferentially with respect to each other upon variations 'of currentflow so as to cause a smaller variation of current flowing through thethermal eleiment than that flowing through the resistor elevment.

5. In a control means for a gaseous discharge ldevice having heatingelements therein a circuit connecting said heaters in series across asupply line, a switch in said circuit which is thermally controlled, athermal element for controlling said switch whichis energized by part ofthe cur- -rent flowing through said circuit and through 'the gaseousdevice, and a resistor element connected in multiple with a circuitincluding said thermal element so as to be energized by Ia part of thecurrent flowing in said first-named circuit with the resistances of themultiple paths of the lcurrents through the two elements varyingdifferentially with respect to each other upon varia- .tions of currentiiow, the thermal element hav- .ing a positive temperature resistancecoeicient and the resistor element having no appreciable positivetemperature resistance coefiicient.

6. In a control means for a gaseous discharge ydevice having heatingelements therein, a circuit connecting said heaters in series across asupply line, a switch in said cir-cuit which is thermally controlled, athermal element for controlling said vswitch which is energized by partof the current owing through said circuit and through the gaseousdevice, and a, resistor element connected in multiple with a circuitIincluding said thermal element so as to be energized by a part of thecurrent iiowing in said first-named circuit with the resistances of themultiple paths of the currents through the two elements varyingdifferentially with respect to each other upon variavtions of currentflow to shift greater changes in current iiow to the resistor element, aresistance having a yhigh temperature resistance coeihcient beingconnected in series with the thermal element.

7. In a control means for .a gaseous discharge device having heatingelements therein, a circuit connecting said heaters in series across asupply line, a normally open switch in said circuit, ther- -mal meansfor closing said switch at the starting of the gaseous discharge devicecomprising a heating element and a resistor element connected acrosssaid switch, said switch `heating element being of a substantiallysmaller resistance than that of the series resistor and said heaterhaving 4a positive temperature coeiiicient of resistance and saidresistor element having no appreciable positive temperature coeiiicientof resistance.

8. In a control means for a gaseous discharge device having heatingelements therein. ,a circuit connecting said heaters in series :across asupply line, a switch in said circuit which is thermally controlled, athermal element for controlling said switch which is energized by partof the current iiowing through said circuit and through the 'gaseousdevice, and a. resistor element connected in multiple with a circuitincluding said thermal element so as tov be energized by :a part of thecurrent flowing in said first named circuit with the resistances of themultiple paths of the currents through the two elements varyingdifferentially with respect to each other upon variations of current nowwith the resistance of the circuit which is in multiple with saidresistor element having a high positive temperature coeicient andv withthe resistor element having little or no positive temperature coeicient.

9. In a control means for a gaseous discharge device having heatingelements therein a circuit connecting said heaters in series across asupply line, a switch in said circuit which is thermally controlled, athermal element for controlling said switch which is energized by partof the current flowing through said. circuit and through the gaseousdevice, and a resistor element connected in multiple with a circuitincluding said thermal element so as to be energized by a part of thecurrent flowing in said rst named circuit with the resistances of themultiple paths of the currents through the two elements varyingdifferentially with respect to each other upon variations of currentflow with the resistance of the circuit which is in multiple with saidresistor element having a high positive temperature coefficient and withthe resistor element having little or no positive temperaturecoefficient and with the thermal element having little or no positivetemperature coeiiicient and a resistance in series therewith having ahigh temperature coefficient.

l0. Starting means for a discharge lamp having a pair of startingiilaments adapted to be Connected across a supply line during thestarting operation, the combination of a thermally controlledtwo-position switch in series with the iilaments adapted in one positiontoenergize them for starting, a thermal element having a high positivetemperature coeiiicient of resistance connected in series with thefilaments for operating the switch at starting, and a resistor having 45no appreciable positive temperature coefficient of resistance connectedwith the thermal element, said resistor and element being continuouslyin circuit with the supply line to be heated thereby during bothstarting and normal operation with 50 the heating current through thethermalr element during normal operation of the lamp being substantiallylower than that during starting.

11. Starting means for a discharge lamp having a pair of startingiilaments adapted to be 55 connected across a supply line during thestarting operation, the combination of a thermally controlledtwo-position switch in series with the filaments adapted in one positionto energize them for starting, a thermal element having a 60 highpositive temperature coeliicient of resistance connected in series withthe filaments for operating the switch at starting, and a resistorhaving no appreciable positive temperature coefficient of resistanceconnected with the thermal 65 element, said resistor and element beingcontinuously in circuit with the supply .line to be heated therebyduring both starting and normal operation with the heating currentthrough .the thermal element during normal operation of the 70 lampbeing substantially lower than that during starting, the switch beingnormally open.

PHILIP SITZER,

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